Book Image

The DevOps 2.1 Toolkit: Docker Swarm

By : Viktor Farcic
Book Image

The DevOps 2.1 Toolkit: Docker Swarm

By: Viktor Farcic

Overview of this book

Viktor Farcic's latest book, The DevOps 2.1 Toolkit: Docker Swarm, takes you deeper into one of the major subjects of his international best seller, The DevOps 2.0 Toolkit, and shows you how to successfully integrate Docker Swarm into your DevOps toolset. Viktor shares with you his expert knowledge in all aspects of building, testing, deploying, and monitoring services inside Docker Swarm clusters. You'll go through all the tools required for running a cluster. You'll travel through the whole process with clusters running locally on a laptop. Once you're confident with that outcome, Viktor shows you how to translate your experience to different hosting providers like AWS, Azure, and DigitalOcean. Viktor has updated his DevOps 2.0 framework in this book to use the latest and greatest features and techniques introduced in Docker. We'll go through many practices and even more tools. While there will be a lot of theory, this is a hands-on book. You won't be able to complete it by reading it on the metro on your way to work. You'll have to read this book while in front of the computer and get your hands dirty.
Table of Contents (22 chapters)
Title Page
Credits
About the Author
www.PacktPub.com
Customer Feedback
Preface
11
Embracing Destruction: Pets versus Cattle

Persisting stateful services on the host


Host-based persistence was very common in the early Docker days when people were running containers on predefined nodes without schedulers like Docker Swarm, Kubernetes, or Mesos. Back then, we would choose a node where we'll run a container and put it there. Upgrades were performed on the same server. In other words, we packaged applications as containers and, for the most part, treated them as any other traditional service. If a node fails... tough luck! It's a disaster with or without containers.

Since serves were prederfined, we could persist the state on the host and rely on backups when that host dies. Depending on the backup frequency, we could lose a minute, an hour, a day, or even a whole week worth of data. Life is hard.

The only positive thing about this approach is that persistence is easy. We would mount a host volume inside a container. Files are persisted outside the container so no data would be lost under "normal" circumstances. If...